Researchers report that people with chronic insomnia show more plasticity and activity than good sleepers in the part of the brain that controls movement. "Insomnia is not a nighttime disorder," says study leader. "It's a 24-hour brain condition, like a light switch that is always on. Our research adds information about differences in the brain associated with it." The researchers say they hope their study opens the door to better diagnosis and treatment of the most common and often intractable sleep disorder that affects an estimated 15 percent of the United States population.